-
Notifications
You must be signed in to change notification settings - Fork 1
/
resolver.go
104 lines (85 loc) · 2.52 KB
/
resolver.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
package rpc
import (
"context"
"flag"
"fmt"
"strings"
"github.com/coreos/etcd/clientv3"
"github.com/coreos/etcd/mvcc/mvccpb"
"google.golang.org/grpc/resolver"
)
const schema = "etcdv3_resolver"
var (
successCode = flag.Int("success code", 0, "rpc reply code")
engineServ = flag.String("engine service",
"toad_ocr_service", "engine service name")
processorServ = flag.String("processor service",
"toad_ocr_preprocessor", "processor service name")
defaultDiscoverUrl = flag.String("default dis url",
"http://localhost:2379", "default etcd service discover address")
)
// resolver is the implementaion of grpc.resolve.Builder
type Resolver struct {
target string
service string
cli *clientv3.Client
cc resolver.ClientConn
}
// NewResolver return resolver builder
// target example: "http://127.0.0.1:2379,http://127.0.0.1:12379,http://127.0.0.1:22379"
// service is service name
func NewResolver(target string, service string) resolver.Builder {
return &Resolver{target: target, service: service}
}
// Scheme return etcdv3 schema
func (r *Resolver) Scheme() string {
return schema
}
// ResolveNow
func (r *Resolver) ResolveNow(rn resolver.ResolveNowOption) {
}
// Close
func (r *Resolver) Close() {
}
// Build to resolver.Resolver
func (r *Resolver) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
var err error
r.cli, err = clientv3.New(clientv3.Config{
Endpoints: strings.Split(r.target, ","),
})
if err != nil {
return nil, fmt.Errorf("grpclb: create clientv3 client failed: %v", err)
}
r.cc = cc
go r.watch(fmt.Sprintf("/%s/%s/", schema, r.service))
return r, nil
}
func (r *Resolver) watch(prefix string) {
addrDict := make(map[string]resolver.Address)
update := func() {
addrList := make([]resolver.Address, 0, len(addrDict))
for _, v := range addrDict {
addrList = append(addrList, v)
}
r.cc.UpdateState(resolver.State{Addresses: addrList})
}
resp, err := r.cli.Get(context.Background(), prefix, clientv3.WithPrefix())
if err == nil {
for i := range resp.Kvs {
addrDict[string(resp.Kvs[i].Value)] = resolver.Address{Addr: string(resp.Kvs[i].Value)}
}
}
update()
rch := r.cli.Watch(context.Background(), prefix, clientv3.WithPrefix(), clientv3.WithPrevKV())
for n := range rch {
for _, ev := range n.Events {
switch ev.Type {
case mvccpb.PUT:
addrDict[string(ev.Kv.Key)] = resolver.Address{Addr: string(ev.Kv.Value)}
case mvccpb.DELETE:
delete(addrDict, string(ev.PrevKv.Key))
}
}
update()
}
}